Description:(From the proposal) Characterization of normal and impaired auditory perception necessarily requires an understanding of how simple and complex auditory signals are perceived and encoded. A void in this area of research is a global or unifying framework with which to understand such processing as it relates to everyday communication in listeners with normal and impaired hearing. This proposal requests support for a comprehensive study focusing on the perception of spectral and temporal patterns characteristic of sounds in the natural environment. One long-term goal is to provide a global explanation of spectral and temporal envelope perception. One specific hypothesis to be tested here is that the perception of envelope changes (spectral or temporal) is consistent with a general set of physical constraints mediated by domain-specific envelope channels in the central auditory system. Two sets of channels are proposed, temporal and spectral, which are tuned to domain-specific envelope frequency and which reflect similar properties (e.g., position invariance) throughout the audio spectrum. It is also proposed that temporal envelope channels might exist that receive both monaural and binaural input. Because so many individuals with cochlear hearing impairment have difficulty processing complex sounds, but relatively little difficulty on many "local" tasks, it is crucial to understand the nature of these deficits and how (putative) domain-specific envelope channels might be affected. The experiments and analyses will provide a substantial contribution to the fields of hearing science, experimental psychology, and clinical audiology.